Electric motor



(No Model.) 4 Sheets-Sheet 1.

W. H. CHAPMAN. ELECTRIC MOTOR.

No. 428,454. Patented May 20, 1,890.

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W. H. CHAPMAN. ELECTRIC MoToR.

No. 428,454. 1241.611444 May 2o, 1890.

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(No Modem 4 Sheets-Sheet 3. W. H. CHAPMAN.

ELECTRIC MOTOR. No. 428,454. Patented May 20, 1890.

(No Model.) 4 Sheets-Sheet '4. W. H. CHAPMAN.

ELECTRIC MOTOR. i No. 428,454. Patented May 20,' 1890.

UNITED STATES PATENT OEEICE.

IVILLIAM II. CHAPMAN, OF PORTLAND, MAINE, ASSIGNOR TO THE GIANT ELECTRICMOTOR COMPANY, OF BOSTON, MASSACHUSETTS.

ELECTRIC MOTOR.

SPECIFICATION forming part of Letters Patent No. 428,454, dated May 20,1890.

Application filed December 30, 1889. SerialNo. 335.307. (No model.) I

To CLZZ wiz/0m it may concern:

Bc it known that I, WILLIAM Il. CHAPMAN, ol' Portland, in the county ofCumberland and State ot' Maine, have invented certain new and usefulImprovements in Electric Motors,

of which the following, taken in connection with the accompanyingdrawings, is a speciiication.

My present invention relates to electric motors of the multipolar type,by which is meant a inotor provided with a Feld-magnet having aplurality of north polesand a plurality of south poles presented to thearmature, andit is an improvement upon the invention described inLetters Patent No. 411,833, granted to Charlesl C. Peck, October l,1889.

My invention consists in certain novel features of construction,arrangement, and combination of parts, which will be readily understoodby reference to the description of the drawings, and to the claimshereinafter given, and in which my invention is clearly pointed out.

Figure l of the drawings is an end elevation of a inotor embodying myinvention. Fig. 2 is a vertical longitudinal section on line l l on Fig.l. Fig. 3 is a vertical transverse section on line 2 2 on Fig. 2. Fig. iis a vertical section online 3 3 on Fig.2 and looking toward the rightof said Fig. 2. Fig. 5 is a diagram illustrating the manner ofconnecting the armature-magnets. Fig. G is a diagram illustrating themanner et connecting the segments of the commutator, the same beingconnected to Fig. 5 by dotted lines. Fig. 7 is a side elevat-ion of oneof the fieldmagnet pole-pieces.

In the drawings, A A are the end t rames of the motor, which also serveas the yokes of the field-magnets, and are bolted to the base-plate A'at their bases and connected together at their tops by the tie-bar A2,as clearly shown in Figs. l and 2. The frames or yokes A A cach haveformed therein a bearing A3, in Which is mounted the shaft I, and lisalso provided with the inwardly-projecting annular rib a., upon whichare bolted the held-magnet cores C, each composed ot a series of thinflat plates l), of soft iron, placed one upon the other and firmlysecured together by rivet-s,

and provided at its inner end with a laterallyprojecting arm C@ theworking-'face or inner surface ot' which is curved tangentially to aplane at right angles to the axis of the shaft B, all as shown in Figs.2, A, and 7. The plates b, of which said field-magnet cores C arecoinposed, may be curved inthe direction of their widths to arcs otcircles concentric with the axis of the shaft B, as shown, or theymay bestraight in the direction named and be arranged tangentially to circlesconcentric to said axis. There must be four or more of these magnetcoresC attached to each trame A, so that each field-magnet shall comprise aplurality of both north and south poles, the number of said poles beingincreased according as it is desired to decrease the speed of revolutionof the motor, as when ity is desired to apply the revolving part ot themotor directly to a shaft that requires to be revolved at acornparatively slow speed. In the machine illustrated in the drawingsthere are eight cores C attached to each frame A, and each fieldmagnethas four north and four south poles. Each of these magnet-cores is Woundwith a coil C2, of suitable insulated wire, held in place by the liberinsulating-plates cc, as shown in Figs. 2 and A, and said coils on eachframe A are connected together in series by wires c, and the two seriesare connected together by wire c2, so that a current ot electricitypassing from the binding-post (Z through the commutator and along thewire d traverses all of the coils C2 of one field-magnet and then allthe coils of the other field-magnet in suecession, and passes oftthrough the bindingpost cl2, as shown in the central portion of thediagram shown in Fig. 5.

The hub of the bearing A3 on one of the frames A has adj ustably securedthereon the segmental plate D, the hub of which is cut open on one sideand provided with an ear e. on each side of said cut, by means of whichand the screw c said plate may be clamped iirmly to the bearing A3, asshown in Figs. l and 2.

The shaft B has iirmly secured thereon, just inside the bearing A3,which carries the plate D, a disk E, of suitable insulating material,and at a suit-able distance therefrom another IOO disk t', of likemateriahsaid disks having in their faces that are toward each otherannular grooves to receive tongues f, formed en the ends of thecemmutator-segments g, and the insulating-plates g', placed betweenthem, as shown in Figs. 2 and 4. The commutatorsegments georrespond innumber to the number of armature-segments used, which in the caserepresented is forty. The shaft B also has secured thereon, so as torevolve therewith, the hub F, having formed in one piece therewith thedisk or iange F at one end, and secured toits other end bythe nut handpins 7L the disk F2, correspondingin size and shape to the disk F. Theinner or adjacent faces of the disks F and F2 have formed thereinperipheral rabbets h2 to receive the inner ends of theradially-projeeting arms 713, made of some strong insulating material,preferably vulcanized fiber, which are secured in position on said disksby screws i, as shown in Figs. l, 2, and Each of these arms h3 hasformed therein near its outerend' a rectangular slot to receive the endof an armaturecorc G, composed, preferably, of a plurality of thin flatsoft-iron plates fastened together by rivets and secured in position bythe set-screws j, as shown in Figs. l, i", and Fach of thesearmature-cores G has wound thereon between the arms 713 a coil 71.4, ofsuitably-insulated wire.

In the motor illustrated in the drawings there are fortyarmature-magnets so arranged that their end surfaees,instead of theirsides, are presented to the action of the two fieldmagnets between whichthey are placed, and revolve about the axis of the shaft B.

It is a well-known fact that in an electric motora greater power can beobtained by the use of a great number of small magnets than from asmaller number of large magnets with the same aggregate weight or massof metal used in each case, and also that the power capacity of anelectromotor is proportioned to the-number of changes of polarity whichtake place in a given time. In consequence of the above facts electricmotors as heretofore constructed have to be run at very high speeds'inorder to transmit any considerable power, and as the speed otl the motoris very much higher than it is desirable to run most machinery that isto bc operated thereby resort is had to gearing to reduce the speed tothe desired number of revolutions per minute. This in many cases isobjectionable en account of the additional weight of the apparatus andthe extra cost of the same. l overcome this objection by using anincreased number of magnet-poles in either or both the field andarmature magnets and connecting the armature in a novel \\'ay,whieh lwill new proceed to describe.

The usual manner of connecting a series of armature-coils with eachother is to join the outside end of the first coil to the inside end ofthe next or second coil, the outside end of the second coil to theinside end of the next or thind coil, and so on around the circle to thelast coil, and the outside end of the last coil to the inside end of thefirst coil, each of the junctions between said coils being connected bya suitable wire with a corresponding segment of the commutator, andbrushes or contact-pins touch the commutator at intervals equal inangular space to the distance apart of two field-poles from each other,as many brushes or contact-pins being used as there are pole ends in thefield-magnet. In my improved motor the forty armaturecoils are arrangedequidistant from each other in a circle concentric with the axis of theshaft B, ten in each quarter of the circle, and those in each quarterare numbered from one to ten, as shown in Figs. 3 and Commeneing witharmature-coil No. l at the top of the motor, I connect the inner end ofsaid coil by the wires ir with the outer end of No. l coil at the rightside of the motor, the

,inner end of that coil by wire 7,2 to the outer end of coil No.1 at thebottom,the inner end of the last-mentioned coil by wire k2 to the outerend of coil No. l at the left side of the motor, these four coilsforming a group of magnets connected together as one magnet in such amanner that whenever a current of electricity is traversing them and oneis reversed all of the four will be reversed at the same instant. Thereare ten groups, each comprising four magnets, each magnet in a grouphaving a like number and connected together in the same manner as groupNo. l. r["he coil No. l at the left side of the motor has its inner endconnected to the outer end of coil No. 2 of the right-hand upper quarterby the wire I, and the coil No. 2 in the lefthand upper quarter of thecircle has its inner end connected by the wire l to the outer end ofcoil No. 3 in the right-hand upper quarter of the circle, and so onuntil coils 3, 4, 5, G, 7, S, and 9 in the left-hand upper quarter ofthe circle are in like manner connected, respectively, to coils i, 5, G,7, S, 0, and l0 inthe righthand upper quarter of the circle bythe wiresZ2, Z5, Z4, lil, l, ZT, and ZH. rlhe inner end of the coil No. l0 in theleft-hand upper quarter of the circle is then connected to the outer endof coil No. l in the right-hand upper quarter of the circle, as shownatm, Fig. 5. The segments of the commutator are numbered to correspondto the numbers of the armaturemagnets in four sets of ten each, as shownin Fig. G. These segments are connected together in ten groups of foureach, as follows: All of the segments numbered l are connected by wiren, those numbered 2 by wire n, 3 b v wire n2, i by wire n3, 5 by wirefn", (i by wire n, 7 by wire n", S by wire fnl, .fl by wire n3, and lOby wire rr, as shown in Fig. Onehalf of the segments in the upper andlower quarters of the circle are provided with binding-screws o o, saidscrews on one side of the commutator-cylinder bein set in the segmentshaving odd numbers, as l, 3, 5, die., and on the opposite side in thesegments having IOO TIO

even numbers, as 2 4 G, &c. The bindingscrews in the segments l, 2, 3,4, 5, 6, 7, 8, 9, and l0 are respectively connected by correspondingly-numbered Wires to the correspondinglynumbered armature-coils in theupper left.-

hand quarter of the circle of armature-mag nets, as shown in Figs. 5 and6, said wires being shown partly in full lines in said figures andpartly by dotted lines connecting said figures. By this method ofconnecting the armatureinagnets together in groups of equal number andof the same phase, and connecting the several groups together in series,and connecting the segments of the commutator together in groups, andsaid groups of commutator-segments to corresponding groups ofarmaturemagnets, I am enabled to very largely increase the number ofmagnets, both field and armature, Without increasing the number ofcommutator-brushes or contact-pins, only two bein g necessary Whateverthe number of the tield and armature magnets, provided that the numberof the armature-magnets shall be som e multiple of the number of polesin the fieldmagnet. What is meant by magnets having the same phase isarmature magnets that at the same instant bear the same relation to afield-magnet pole-that is, are at the same distance from and on the sameside of a fieldmagnet pole with reference to the direction of therevolution. The segmental plate D has set therein twoinwardly-projecting studs p and p', on which are mounted, respectively,the brush-holder blocks q and q', provided with suitable slots toreceive the commutatorbrushes Ir and r', which are secured therein intheir proper positions by the set-screws r2 and fri", respectively. Thebrushes are pressed into contact with the peripheral surface of thecommutator-eylinder by the tension of coiled springs s, surrounding thestuds and jp', one end of each of which is made fast to the adjustablecollar rl on its stud and the other end to the brush-holder, one only ofsaid springs being shown in Fig. 2. rllhe brushes are so arranged andadj usted that their points of contact with the peripheral surface ofthe coinmutator-cyliuder are at the same angular distance from eachother as the pole ends of the field-magnets are apart. are made of ironand form the yokes for the field-magnet cores.

By forming the lateral extensions C on the field-magnet cores C andcurving their active faces, as hcreinbetore described, a great advantageis obtained in an increased effectiveness ot the motor due to the factthat several armature-magnets are Wit-hin the iniiuence of eachfield-magnet pole at the same time and are being acted upon thereby witha greater or less degree of force, according to the distance betweensaid armature-maguets and said curved surface. In the case of .tieldmagnets not having said extensions and curved surface each armature-poleis within the influence of the field-magnet pole only The frames A A.

for a very short space of time, and only one of the armatureepoles isWithin the influence of said iieldenagnet pole at the same time.

Another important feature of inyinvention is making the supports of thearmature-cores of vulcanized fiber or other strong insulating material,whereby a defect in the insulation of the Wire of one armature-coil isprevented from affecting either of the other coils.

Another important feature of this invention is'the ability to use alarge number of poles in either er both the field and armature magnetswith only two commutator-brushes er contact-pins, whereby a considerablesaving is made in the iirst cost of the commutator and a great saving intime in fitting and adjusting said brushes, as Well as expense inrepairs caused by replacing so many brushes When they Wear out, andrepairing the daniage done to the commutator-cylindcr by the Wear of Aalarge number of brushes.

-What I claim as new, and desire to secure by Letters Patent of theUnited States, is-

l. ln a multipolar motor, the combination of a plurality of groups ofequal number of armature-magnets arranged in a circle about a commoncenter, the magnets in each group being located equidistant from eachother about said circle and connected permanently together as onemagnet, and the several groups being connected to each other insuccession, a commutator having as many segment-s as there arearmattire-magnets and arranged in corresponding groups, the segments incach group being connected together as one, and each group of segmentsbeing connected with corresponding points of junction of the severalgroups of armature-maguets, and a fieldmagnet composed of a series ofelectric helices and having a plurality of both north and south poleends, the cores and pole ends of said helices being each made up of aseries of plates which extend the Whole length of the core to the poleend, and having its pole end expanded laterally and curved tangentiallyto a plane at right angles to the axis of the revoluble portion of themotor.

2. In an electric motor, an armature having a series of magnet-coresarranged with their magnetic axes parallel to the axis of revolution ofthe revoluble portion of the motor, and mounted in supports made ofvulcanized fiber or other suitable insulating material, whereby theseveral cores are insulated from each other, so that if the insulationof the Wire of one coil is defective it shall not affect the othercoils.

ln testimony whereof I have signed my name to this specification, in thepresence of tivo subscribing Witnesses, on this 27 th day of December,A. D. 1889.

VILLIAM ll. CHAPMAN Vr'vitnesscs:

N. C. LOMBARD, WALTER E. LOMBARD.

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